Hydraulic control system for selfpropelled excavator



lMarczh 9, 1965 R. METAILLER HYDRAULIC CONTROL SYSTEM FOR SELF-PROPELLED EXCAVATOR Filed April 9, 1963 5 Sheets-Sheet l March 9, 1965 R. METAILLER 3,172,552'- HYDRAULIC CONTROL SYSTEM FOR SELF-PROPELLED ExcAvAToR Filed April 9, 1965 5 Sheets-Sheet 2 March 9, 1965 R. METAILLER 3,172,552

HYDRAULIC coNTRoL SYSTEM FOR SELF-'PROPELLED ExcAvA'roR Filed April 9, 1963 5 Sheets-Sheet 3 A im@ H" March 9', 1965 R. MEMILLER 3,172,552

HYDRAULIC CONTROL SYSTEM FOR SELF-PROPELLED EXCAVATOR Filed April 9, 1963 5 Sheets-Sheet 4 March 9, 1965 R. METAILLER 3,172,552

YHYDRAULIC coNTRoL SYSTEM FOR sELF-PRoPELLED ExcAvAToR Filed April 9, 1963 5 Sheets-Sheet 5 United States Patent O 3,172,552 HYDRAUMC CNTRL SYSTEM FOR Siliii- PRPELLED EXCAVATOR Roger Metailler, Paris, France, assigner to Societe Auxiliaire de lEntreprise (Atmen), Paris, France Filed Apr. 9, 1963, Ser. No. 271,741 d Claims. (Cl. 214-138) This invention relates in general to excavators and has specific reference to a hydraulic control system for a self-propelled excavator comprising a slewing platform, one or a plurality of working equipments pivotally mounted on said slewing platform, for example a boom or jib pivotally mounted on said platform, a bucket arm or clipper handle pivoted on the outer end of said boom and a bucket or dipper pivoted in turn on the outer end of said dipper arm or handle, and mechanical means arranged under the aforesaid platform for propelling the machine.

In public work or earth-moving machines of the type broadly dened hereinabove hydraulic control systems or gears are frequently provided, but in hitherto known hydraulic control systems or gears certain pumps feed a plurality of members adapted to operate simultaneously, and therefore the movements impressed to these members are obviously attended by a certain irregularity.

It is the chief object of this invention to provide a hydraulic control system for an excavator of the type broadly set forth hereinabove, wherein each pump actuates either a single one of the mechanical members to be operated or two mechanical members of which the simultaneous operation must be strictly avoided under any circumstances.

This hydraulic control system comprises a control unit incorporating iive pairs of junction-points permitting, by properly connecting receiving units to these pairs of junction-points, adapting of the system to the equipment of an excavator having its pivoting or oscillating elements operated by means of drums or dubleacting cylinders and its frame mounted either on crawler tracks or on heavy tyres, and this control unit comprising four hydraulic pumps connected in parallel to a fluid reservoir and driven from the power unit (for instance the diesel or like thermal engine) of the machine is characterized in that two of said hydraulic pumps are adapted to feed hydraulic uid under pressure each to one pair of junction-points feeding respectively hydraulic motors controlling two of said pivoting elements, another pump delivering in parallel hydraulic iiuid to a pair of junction-points for feeding in turn the motor associated with another pivoting element, and another pair of junction-points leading to a rotary joint in said slewing platform, the last pump delivering in parallel hydraulic duid under pressure to a hydraulic motor for slewing the platform and to another pair of junction-points leading to said rotary joint under said platform which is prol vided for feeding the hydraulic motors driving mechanican means mounted under said platform for propelling the excavator forwards or backwards.

It will be seen that in this arrangement the lirst and second pumps each actuate a sinele element, that is, one of the elements pivotally mounted on the slewing platform. The third pump feeds the motor driving the third pivoting element and also one of the motors driv ing the mechanical means mounted under the platform for propelling the excavator. These two last-named motors are never operated simultaneously. The same applies to the two motors operable from the fourth pump since these two motors produce the one the slewing movements of the platform relative to the undercarriage, and the other the forward or backward translation of this undercarriage.

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With the foregoing and other objects in view, the invention resides in the novel arrangement and combination of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed may be made within the scope of what is claimed without departing from the spirit of the invention.

Other objects and advantages will become apparent from the following description taken in conjunction with the accompanying drawings in which:

FIGURE lis a general diagram showing the control system of this invention as applied to a crawler-mounted machine wherein the pivoting working elements are actuated by means of drums and ropes;

FIGURES 2 to 8 illustrate various details of the assembly shown in FIG. 1;

FIG. 9 is an assembly diagram showing the complete arrangement as applied to a machine wherein, as in the example of FIG. 1, three pivoting working elements are actuated by means of drums and ropes, the machine being mounted on pneumatic tyres;

FIGURE l0 illustrates on a larger scale one portion of the diagram of FIG. 9 to show a detail of that portion of the system which drives the tyre-mounted wheels of the machine undercarriage;

FIGURE 1l is the assembly diagram of the control system as applied to a machine wherein three pivoting working elements are operated by means of double-acting hydraulic cylinders; and

FIGURE 12 is another assembly diagram of the control system as applied to a machine wherein two pivoting working elements are operated by means of drum-andrope units, the third element being operated by means of a hydraulic cylinder.

The platform 1 of FIG. l adapted to be slewed about the axis 2 as shown in FIG. 2 is connected to the central portion 37 of the undercarriage through a race 5. This platform 1, as shown in FIG. 3, comprises:

A thermal engine 6 drivingly connected through a coupling 7 to a transfer gearing 1S which, through the shaft 8 on which a pinion 9 mounted for free rotation may be rendered solid with this shaft 8 through a slid-ing hub 10, is in meshing engagement with pinions 11, 12 solid with shafts 14, 13, respectively, drives the hydraulic pumps 16, 17 mounted in parallel. A boom-luing drum 23 shown in FIG. 4 is driven from a hydraulic motor 18 through bevel gears 19, 2i) and a sleeve 22 rigid with the rope drum 23. The sleeve 22 is mounted for free rotation on shaft 2l rigid with a gear case 24. A set of two drums 23 for hoisting the load or the two-rope grab bucket, or a drag line bucket (or any other desired equipment) illustrated in FIG. 5 comprises the elements corre# spend-ing to those of FIG. 4 and shown as being mounted on a stationary shaft rigid with gear cases 24. A rotarymotion or slewing mechanism produces the slewing motion of the platform 1 from a hydraulic motor 1S through bevel gears 19, 20 rigid with a vertical shaft 26 mounted for loose rotation in a gear case 27. To this end atoothed wheel 29 rigid with shaft 26 is in constant meshing engagement with the circular rack of a guide race 5, this rack being secured on the central portion 37 of the frame or undercarriage of the machine. The gear case 27 is mounted for free rotation with respect tothe platform 1 through the medium of bushings or bear-ings 28. A rotary joint 3i) mounted between the platform 1 and the central portion 37 of the undercarriage permits, as shown in FIG. 2, the circulation of uid under pressure from the slewing platform to the undercarriage irrespective of the relative positions of the platform and undercarriage. The undercarriage is mounted on a pair of lateral crawler tracks 3 each provided, as shown in FIG.

6, with a separate driving unit comprising a hydraulic motor 18 and a mechanical transmission consisting of pinions 19, 20, 32, 33 and shafts 31, 35 enclosed in the gear case 34. This mechanism is adapted to drive a sprocket 36 driving in turn the crawler tracks 3.

The pumps 16 and 17 driven from motor 6 as shown in FIG. 3 have their suction port connected to the reservoir 54 and draw oil therefrom through a filter 55.

A boom luiling rope 110 is wound on the luf`n`ng drum 23 from the mechanism contained in the gear case 24 and the hydraulic motor 18. This motor is fed from a pump 17 delivering the iiuid under pressure through a pipe line 56. The fluid pressure is controlled by a pressure limiter 57 adapted to discharge the excess oil into the reservoir 54 if necessary. A distributor 58 comprises a neutral position wherein the motor is not fed with oil or like uid under pressure, the latter returning in this case to the reservoir through the line 71; in this position the uid under pressure circulates in the pipe line on the junction side 59, so that the motor is driven in the load-hoisting direction and the fluid returned through the pipe line on the other junction side 60, and an opposite position wherein the fluid flows through junction side 60, the motor in this case being driven in the load lowering direction and the fluid returned through the pipe line on junction side 59. A pressure equalizer 62 is adapted to by-pass the feed and return lines of hydraulic motor 18, should the pressure within the motor exceed that of pump 17. A monitored valve 61 opens the circuit through the junction side 59 when the pressure -is delivered through the other junction side 60 for lowering the load. The opening of junction side 59 and therefore the load lowering speed are controlled by a calibration of valve 61. Therefore, this calibration makes it necessary to operate the engine 6 for lowering the load. To permit the control of the free fall of the load a mechanical clutch or a hydraulic motor 18 with a zero output position may be provided between the output shaft of motor 18 and pinion 19.

Ropes 108 and 109 are controlled by units similar to those described hereinabove and fed with uid from pumps 16.

The slewing wheel 29 is driven from the mechanism contained in the gear case 27 and the hydraulic motor 18 is fed with fluid under pressure from pump 17 through the pressure limiter 57 and distributor 58. The pressure equalizer 62 is adapted to by-pass the feed and return lines of motor 18 should the pressure within this motor exceed that of the fluid delivered by pump 17 and controlled by limiter 57.

The forward and backward motion of the crawlermounted undercarriage is obtained by means of two units each comprising a mechanism (contained in a gear case 34) and hydraulic motor 18. Each motor 18 is fed through one of the two pumps 17 through a pipe line 80 leading to a distributor 58 associated with a pressure limiter 57. The uid under pressure Hows through the rotary joint 30 mounted between the slewing platform 1 and the central portion of undercarriage 37. The combination of the positions of distributor 58 permits of driving the two crawler tracks either simultaneously in the same direction (either forwards or backwards) for operating the machine along a straight course, or in opposite directions for turning the machine, another alternative consisting in driving only one crawler, the other remaining stationary, for long-radius turns. A pressure equalizer 62 is adapted to by-pass each motor 18 in case of overpressure resulting from an abnormal resistance to the driving effort.

The platform slewing mechanism comprises a damping device as shown in FIGS. 7 and 8. To this end the case 27 carries a lug 85 engaged by rods having a part-spherical head 86 urged against the lug 85 by compression springs 87 reacting against the platform 1 by means of stop members 88. When the slewing motion is stopped abruptly and during the opening of the equalizing valve 62, the inertia of the mass constituted by the platform 1 is transmitted to the gear case 27 rotating freely with respect to this platform 1, and absorbed according to the direction of rotation by one or the other spring 87. To permit the rotation of case 27 in relation to platform 1, flexible pipe sections 77, 78 are inserted in the pipe lines leading to the motor 18 driving the pinion 29.

The above-described component elements have no mechanical connection whatsoever with one another, so that their mounting on platform 1 is greatly facilitated. The hydraulic pipe lines comprise five pairs of junctionpoints 59-60, 63-64, 65-66, 112-113 and 114-115 for connecting or disconnecting the machine elements fed through the pairs of junction points respectively.

It will be noted that the arrangement shown in FIG. 1 Iand described hereinabove comprises a control unit A feeding the pairs of hydraulic junction points 59-60, 61-63, 65-66, 112-113 and 114-115 and two controlled units, that is unit B1 connected to the rst three pairs of hydraulic junction-points for actuating the three osciliating motions of the machine, for example the lufting motion of the boom on the platform, the motion olf the dipper arm and the motion of the bucket or dipper proper on said arm, and unit C1 connected on the last two Ipairs of hydraulic junction-points `for controlling the movements of the machine.

In the diagram of FIG. 9 showing the adaptation of the hydraulic control system to a tyre-mounted machine having its three pivoting elements controlled by drums and ropes, the control unit A and the receiving unit B lare also provided, exactly as in the preceding embodiment, but another unit C2 is substituted for unit C1. This unit C2 is connected -to the pair of hydraulic junction-points 112-113, the pair of junction-points 114-115 being inoperative in this case. The undercarriage or chassis 4 of the machine carries lin this example a propelling control unit consisting of a hydraulic motor 40 driving -a torque converter 41. The hydraulic motor 40 is fed from a pump '17 of unit A through the medium of pipe line 80, pressure limiter 57 of distributor 58 and pipe lines 81, 82 connected to the pair of junction-points 112-113, the fluid being circulated under the frame to the aforesaid unit C2 through a rotary joint 30.

In this case, the pair of junction-points 114-115 remains inoperative.

FIGURE 10 shows the torque converter 41 driven yfrom the hydraulic motor 40. In order to widen the range of speeds of the excavator, the gearbox 42 mounted on the output shaft of the torque converted is a two- -speed change gear having pinions 91, 92 rotatably solid with the out-put shaft 98 of torque converter 41. These pinions are in meshing engagement with toothed wheels 94, 96 revolving freely on shaft 93 and adapted to be rendered separately `solid with shaft 93 by means of a sliding hub 95. If desired, the gear case 42 may be mounted directly on the torque converter 41.

In the diagram of FIG. l1 showing the application of the control system to a machine having its three pivoting elements actuated by three double-acting cylinders there is also shown, as in all the combinations according to this invention, the control unit A of FIGS. l and 7, but in this case a unit B2 is substituted for the receiving unit B1 of these two figures. This unit B2 comprises a boom 103 the vertical movements of which are controlled by a hydraulic cylinder 100 fed with fluid under pressure through pipe lines connected to the pair of junction-points 65-66, an arm 104 the pivotal movements of which on the outer end of the boom are controlled through a cylinder 101 fed through pipe lines connected to the pair of junction-points 63-54, and a bucket 105 pivoted in turn on the outer end of the arm yby means of a cylinder 102 fed through pipe lines connected to the pair of junctionpoints 59-60.

In the diagram of FIG. 12 showing the manner in which 3 the control system is adaptable to an earth moving machine having two pivoting elements actuated through drums and ropes, with `a third pivoting element actuated through a double-acting hydraulic cylinder, the unit B2 of the control system illustrated in FIG. is replaced by a unit B3 comprising a boom 166 and a clipper arm 167 pivoted on the outer end of this boom. The vertical movements and the boo-m and dipper arm are controlled through ropes lil-S and 199 connected to drum 23. The dipper arm 197 carries a bucket lil pivoted by means of a double-acting cylinder 102 fed through pipe lines connected to the pair of junction-points 59-69. Two motors 18 for driving the drums 23 are connected to the two pairs of junctionepoints 63-64 and 65-66, and pressure equalizing means 62 are interposed there-between.

Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modifications and variations ma f be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.

What I claim is:

l. A hydraulic control system :for an excavator having a frame, a platform mounted for slewing motion on said frame, a thermal engine mounted on said platform, three swinging Working members consisting of a boom mounted for luing motion about a horizontal axis on said platform, of a bucket arm pivotally mounted on the outer end of said boom, and of a bucket pivotally mounted on the outer end of said bucket arm, of `a mechanism mounted on said frame under said platform for imparting a movement of translation tothe excavator and comprising a pair of drive shafts and `a pair of crawler tracks driven from said drive shafts, respectively, and of another mechanism for controlling the slewing mot-ion of said platform on said frame, said system comprising four pum-ps rotatably driven at the same speed from said engine, a first hydraulic motor mounted on said platform and driving on the one hand the first one of said swinging members and a first distributor for said hydraulic motor, a second hydraulic motor mounted under said platform and driving one of said drive shafts, a rotary seal axially mounted through said platform, a second distributor mounted on said platform and connected through said rotary seal to said second hydraulic mo-tor, said first and second distirbutors being connected in parallel to the first one of said four pumps, a third and a fourth hydraulic motor-s mounted yon said platform and adapted to control respectively said second and third swinging working members, a third and `a fourth distributors controlling respectively said third and yfourth hydraulic motors and yfed respectively from said second and third pumps, a fifth hydraulic motor mounted on said platform for actuating the mechanism controlling the slewing movements of said platform on said frame, and a fifth distributor for said fifth motor, a sixth hydraulic Imotor mounted under said platform for driving lsaid other drive shaft, a sixth distributor mounted on said platform and connected through said rotary seal to said sixth motor, said fifth and sixth distributors being connected in parallel to said four pump.

2. A hydraulic control system as set forth in claim l for an excavator wherein Ithe mechanism for controlling the slewing movements of the platform relative to said frame comprises a toothed annulus 'fastened on said frame, a gear case rotatably mounted on said frame, an shaft rotatably mounted in said case, a pinion keyed on the end of said axial shaft and meshing with said toothed annulus, a lug rigid with said case, resilient means mounted on said platform for -resiliently urging said case for rotation towards a mean position in relation to said platform, and a drive shaft extend-ing radially from said case and rotatably connected to .said axial shaft in said case, said fifth hydraulic motor 'coupled to said drive shaft extending radially from said case and flexibly mounted on said platform being fed through flexible hydraulic pipe lines whereby said fifth motor may follow the low-amplitude pivotal movements of said case in relation to said platform against the resistance of said resilient means.

3. A hydraulic ycontrol system as set for-th in claim l, :for an excavator having its mechanism mounted on the rframe under said platform for imparting the movements of translation to the excavator consists of a tire-mounted power-driven set of wheels, of a differential and of a single drive shaft driving said differential, wherein said drive shaft is coupled to said second hydraulic motor, said sixth distributor being kept in its closed position.

4. A hydraulic control system as set forth in claim 3, comprising in addition a torque :converter and a changespeed mechanism interposed between said second hydraulic motor and the drive shaft driving said differential.

References Cited by the Examiner UNITED STATES PATENTS 2,536,724 l/5l Clay 214-135 2,979,908 4/61 Shook 214-432 3,053,044 9/62 Gresty 60-53 3,108,701 10/63 Hodgson 2l4-l40 HUGO O. SCHULZ, Primary Examiner. 

1. A HYDRAULIC CONTROL SYSTEM FOR AN EXCAVATOR HAVING A FRAME, A PLATFORM MOUNTED FOR SLEWING MOTION ON SAID FRAME, A THERMAL ENGINE MOUNTED ON SAID PLATFORM, THREE SWINGING WORKING MEMBERS CONSISTING OF A BOOM MOUNTED FOR LUFFING MOTION ABOUT A HORIZONTAL AXIS ON SAID PLATFORM, OF A BUCKET ARM PIVOTALLY MOUNTED ON THE OUTER END OF SAID BOOM, AND OF A BUCKET PIVOTALLY MOUNTED ON THE OUTER END OF SAID BUCKET ARM, OF A MECHANISM MOUNTED ON SAID FRAME UNDER SAID PLATFORM FOR IMPARTING A MOVEMENT OF TRANSLATION TO THE EXCAVATOR AND COMPRISING A PAIR OF DRIVE SHAFTS AND A PAIR OF CRAWLER TRACKS DRIVEN FROM SAID DRIVE SHAFTS, RESPECTIVELY AND OF ANOTHER MECHANISM FOR CONTROLLING THE SLEWING MOTION OF SAID PLATFORM ON SAID FRAME, SAID SYSTEM COMPRISING FOUR PUMPS ROTATABLY ON SAID FRAME, THE SAME SPEED FROM SAID ENGINE, A FIRST HYDRAULIC MOTOR MOUNTED ON SAID PLATFORM AND DRIVING ON THE ONE HAND THE FIRST ONE OF SAID SWINGING MEMBERS AND A FIRST DISTRIBUTOR FOR SAID HYDRAULIC MOTOR, A SECOND HYDRAULIC MOTOR MOUNTED UNDER SAID PLATFORM AND DRIVING ONE OF SAID DRIVE SHAFTS, A ROTARY SEAL AXIALLY MOUNTED THROUGH SAID PLATFORM, A SECOND DISTRIBTOR MOUNTED ON SAID PLATFORM AND CONNECTED THROUGH SAID ROTARY SEAL TO SAID SECOND HYDRAULIC MOTOR, SAID FIRST AND SECOND DISTRIBUTORS BEING CONNECTED IN PARALLEL TO THE FIRST ONE OF SAID FOUR PUMPS, A THIRD AND A FOURTH HYDRAULIC MOTORS MOUNTED ON SAID PLATFORM AND ADAPTED TO CONTROL RESPECTIVELY SAID SECOND AND THIRD SWINGING WORKING MEMBERS, A THIRD AND A FOURTH DISTRIBUTORS CONTROLLING RESPECTIVELY SAID THIRD AND FOURTH HYDRAULIC MOTORS FED RESPECTIVELY FROM SAID SECOND AND THIRD PUMPS, A FIFTH HYDRAULIC MOTOR MOUNTED ON SAID PLATFORM FOR ACTUATING THE MECHANISM CONTROLLING THE SLEWING MOVEMENTS OF SAID PLATFORM ON SAID FRAME, AND A FIFTH DISTRIBUTOR FOR SAID FIFTH MOTOR, A SIXTH HYDRAULIC MOTOR MOUNTED UNDER SAID PLATFORM FOR DRIVING SAID OTHER DRIVE SHAFT, A SIXTH DISTRIBUTORS BEING CONPLATFORM AND CONNECTED THROUGH SAID ROTARY SEAL TO SAID SIXTH MOTOR, SAID FIFTH AND SIXTH DISTRIBUTORS BEING CONNECTED IN PARALLEL TO SAID FOUR PUMP. 